High Temperature Resistant Insulating Film

This international application claims priority to Chinese Patent Application No. 202211241696.8, filed Oct. 11, 2022, to Chinese Patent Application No. 202222677854.6, filed Oct. 11, 2022, and to Chinese Patent Application No. 202311080805.7, filed Aug. 25, 2023. The entireties of Chinese Patent Application No. 202211241696.8, Chinese Patent Application No. 202222677854.6, and Chinese Patent Application No. 202311080805.7 are incorporated herein by reference.

The present application relates to the field of films, in particular to a high-temperature-resistant insulating film.

Insulation films are used to isolate various electronic devices or components to prevent failures caused by short circuits, breakdowns, etc., between or within electronic devices or components. Some insulating films also need to have high-temperature resistance to reduce the impact of localized high temperatures on electronic devices or components, ensuring the normal operation of various electronic devices or components.

The object of the present application is to provide a high-temperature-resistant insulating film for use in electronic devices or components, which meets the insulating requirements of electronic devices or components while also possessing excellent high-temperature resistance. Additionally, this high-temperature-resistant insulating film possesses excellent mechanical performance to meet the requirements of the usage environment.

The present application provides, in a first aspect, a method for producing a high-temperature-resistant insulating film, which comprises the following steps: applying an uncured material to the upper surface and the lower surface of the mica layer for high-temperature-resistant insulation; and curing the uncured material to obtain an upper additional layer of high-temperature-resistant insulation attached to the upper surface of the mica layer for high-temperature-resistant insulation and a lower additional layer of high-temperature-resistant insulation attached to the lower surface of the mica layer for high-temperature-resistant insulation; the outer surface of the upper additional layer of high-temperature-resistant insulation forms the first outer surface of the high-temperature-resistant insulating film for high-temperature-resistant insulation, and the outer surface of the lower additional layer of high-temperature-resistant insulation forms the second outer surface of the high-temperature-resistant insulating film for high-temperature-resistant insulation.

According to the aforementioned first aspect, the step of applying the uncured material to the upper surface and the lower surface of the mica layer for high-temperature-resistant insulation is carried out through processes such as roll coating, blade coating, or spray coating.

According to the aforementioned first aspect, the step of curing the uncured material is initiated through radiation.

2 According to the aforementioned first aspect, the radiation involves exposure to ultraviolet light, with a wavelength of 300-370 nm, and a radiation intensity of 60-120 w/cm.

According to the aforementioned first aspect, the coating thickness of the uncured material is 0.02-0.05 mm.

According to the aforementioned first aspect, the uncured material is epoxy resin coating, and the step of curing the uncured material is by heating the uncured material to 60-120° C.

According to the aforementioned first aspect, the coating thickness of the uncured epoxy resin coating is 0.02-0.1 mm.

According to the aforementioned first aspect, the uncured material is PU coating, and the step of curing the uncured material is by drying.

According to the aforementioned first aspect, the thickness of the mica layer for high-temperature-resistant insulation is 0.1-3 mm, and the thickness of the cured upper additional layer of high-temperature-resistant insulation and the lower additional layer of high-temperature-resistant insulation is within 100 μm.

The present application provides, in a second aspect, a method for producing a high-temperature-resistant insulating film, which comprises the following steps: applying adhesive to the upper surface and the lower surface of the mica layer for high-temperature-resistant insulation to obtain the upper bonding layer of high-temperature-resistant insulation and the lower bonding layer of high-temperature-resistant insulation, respectively; bonding the upper additional layer of high-temperature-resistant insulation to the upper surface of the mica layer for high-temperature-resistant insulation through the upper bonding layer of high-temperature-resistant insulation, and bonding the lower additional layer of high-temperature-resistant insulation to the lower surface of the mica layer for high-temperature-resistant insulation through the lower bonding layer of high-temperature-resistant insulation, such that the outer surface of the upper additional layer of high-temperature-resistant insulation forms the first outer surface of the high-temperature-resistant insulating film for high-temperature-resistant insulation, and the outer surface of the lower additional layer of high-temperature-resistant insulation forms the second outer surface of the high-temperature-resistant insulating film for high-temperature-resistant insulation.

According to the aforementioned second aspect, the step of bonding the upper additional layer of high-temperature-resistant insulation to the upper surface of the mica layer for high-temperature-resistant insulation through the upper bonding layer of high-temperature-resistant insulation, and bonding the lower additional layer of high-temperature-resistant insulation to the lower surface of the mica layer for high-temperature-resistant insulation through the lower bonding layer of high-temperature-resistant insulation, comprises the following: applying a plastic film to each of the upper bonding layer of high-temperature-resistant insulation and the lower bonding layer of high-temperature-resistant insulation, and bonding the plastic films to the upper surface and the lower surface of the mica layer for high-temperature-resistant insulation, respectively through a lamination process, thereby obtaining the upper additional layer of high-temperature-resistant insulation and the lower additional layer of high-temperature-resistant insulation.

According to the aforementioned second aspect, the temperature and pressure of the lamination process are 95-125° C. and 3-25 MPa, respectively.

According to the aforementioned second aspect, the speed of application of the upper additional layer of high-temperature-resistant insulation and the lower additional layer of high-temperature-resistant insulation is 2-20 m/min.

According to the aforementioned second aspect, the coating thickness of the upper bonding layer of high-temperature-resistant insulation and the lower bonding layer of high-temperature-resistant insulation is 0.01-0.05 mm.

According to the aforementioned second aspect, the lamination process ensures that the total thickness of the upper additional layer of high-temperature-resistant insulation and the upper bonding layer of high-temperature-resistant insulation, as well as the total thickness of the lower additional layer of high-temperature-resistant insulation and the lower bonding layer of high-temperature-resistant insulation, are both within 100 μm.

Various specific embodiments of the present application will be described below with reference to the accompanying drawings that form a part of the present specification. It should be understood that while terms denoting orientation, such as “front,” “rear,” “upper,” “lower,” “left,” “right,” “top,” “bottom,” “inside,” “outside,” etc., are used in the present application to describe various exemplary structural parts and elements of the present application, these terms are used herein for convenience of illustration only and are determined based on the exemplary orientations shown in the accompanying drawings. Since the examples disclosed in the present application may be disposed in different orientations, these terms denoting orientation are for illustrative purposes only and should not be considered as limiting.

In the present application, unless otherwise specified, all equipment and materials may be purchased from the market or are commonly used in the industry. The methods in the following examples, unless specifically stated, are conventional methods in this field.

The mica layer in the present application is formed by bonding mica paper or mica powder with an adhesive and then subjecting it to heat pressing; wherein, mica accounts for approximately 90% of the weight, and the adhesive accounts for approximately 10% of the weight. As an example, the adhesive is organic silicone glue. The mica paper or mica powder may be golden mica, white mica, or other synthetic mica. In certain examples, the mica layer is a commercially available mica sheet or mica board.

1 1 FIGS.A andB 1 1 FIGS.A andB 100 100 101 102 103 101 102 103 illustrate the specific structure of a high-temperature-resistant insulating filmaccording to an example of the present application. As shown in, the high-temperature-resistant insulating filmcomprises a mica layer, an upper additional layer, and a lower additional layer. As an example, the thickness of the mica layeris 0.1-3 mm, and the thickness of the upper additional layerand the lower additional layeris within 100 μm.

102 101 102 100 102 101 103 101 103 100 103 101 1 1 FIGS.A andB The inner surface of the upper additional layeris attached to the upper surface of the mica layer, and the outer surface of the upper additional layerforms the first outer surface of the high-temperature-resistant insulating film(i.e., the upper outer surface). In the example shown in, the inner surface of the upper additional layeris directly attached to the upper surface of the mica layer. The inner surface of the lower additional layeris attached to the lower surface of the mica layer, and the outer surface of the lower additional layerforms the second outer surface of the high-temperature-resistant insulating film(i.e., the lower outer surface). In the present example, the inner surface of the lower additional layeris directly attached to the lower surface of the mica layer.

102 103 101 102 103 102 103 102 103 102 103 101 102 103 The upper additional layerand the lower additional layerare made of materials different from the mica layer. The upper additional layerand the lower additional layermay be made of the same material or different materials. In the present example, the upper additional layerand the lower additional layerare made of the same material. The material of the upper additional layerand the lower additional layerhas an uncured state and a cured state. When the material of the upper additional layerand the lower additional layeris in an uncured state, they are applied and bonded to the upper surface and the lower surface of the mica layer, respectively. When the material of the upper additional layerand the lower additional layeris in a cured state, they form the upper reinforcement layer and the lower reinforcing layer, respectively. The upper reinforcement layer and the lower reinforcement layer refer to additional layers that enhance the mechanical performance of the mica layer.

102 103 101 102 103 102 103 102 103 2 The cured state of the upper additional layerand the lower additional layeris a chemically crosslinked cured coating. During the production process, the uncured material is first applied to the upper surface and the lower surface of the mica layerthrough processes such as roll coating, blade coating, or spray coating; next, the uncured material is converted to the cured state to obtain the cured upper additional layerand the lower additional layer. In some examples, the conversion of the upper additional layerand the lower additional layerfrom an uncured state to a cured state is initiated through radiation. In a specific example, the uncured material that may be cured by radiation is a commercially available UV light-curable adhesive coating with a coating thickness of 0.02-0.05 mm, and this coating may be transformed into a cured state by exposure to ultraviolet light with a wavelength of 300-370 nm and a radiation intensity of 60-120 w/cm. In some other examples, the conversion of the upper additional layerand the lower additional layerfrom an uncured state to a cured state is achieved through heating or drying. In a specific example, the uncured material that may be cured through heating or drying is an epoxy resin coating with a coating thickness of 0.02-0.1 mm, and this coating may be converted to a cured state through heating to 60-120° C. In another specific example, the uncured material that may be cured through heating or drying is a PU (polyurethane) coating, and this coating may be converted to a cured state by air-drying.

1 FIG.C 1 1 FIGS.C andD 130 130 101 102 122 103 123 101 102 122 103 123 102 103 101 122 123 101 and ID illustrate the specific structure of a high-temperature-resistant insulating filmaccording to another example of the present application. As shown in, the high-temperature-resistant insulating filmcomprises a mica layer, an upper additional layer, and an upper bonding layer, as well as a lower additional layerand a lower bonding layer. As an example, the thickness of the mica layeris 0.1-3 mm, the total thickness of the upper additional layerand upper bonding layeris within 100 μm, and the total thickness of the lower additional layerand lower bonding layeris also within 100 μm. In the present example, the upper additional layerand the lower additional layerdo not have adhesive properties; in other words, they cannot directly adhere to the upper surface and the lower surface of the mica layeron their own. Meanwhile, the upper bonding layerand lower bonding layerdo not provide reinforcement; in other words, they cannot enhance the mechanical performance of the mica layer.

1 1 FIGS.C andD 102 101 122 102 130 103 101 123 103 130 In the example shown in, the inner surface of the upper additional layeris attached to the upper surface of the mica layerthrough the upper bonding layer, and the outer surface of the upper additional layerforms the first outer surface of the high-temperature-resistant insulating film(i.e., upper outer surface). The inner surface of the lower additional layeris attached to the lower surface of the mica layerthrough the lower bonding layer, and the outer surface of the lower additional layerforms the second outer surface of the high-temperature-resistant insulating film(i.e., lower outer surface).

102 103 101 102 103 102 103 102 103 122 123 102 103 101 122 123 The upper additional layerand the lower additional layerare made of materials different from the mica layer. The upper additional layerand the lower additional layermay be made of the same material or different materials. In the present example, the upper additional layerand the lower additional layerare made of the same material. In some examples, the upper additional layerand the lower additional layerare plastic films, such as PET (polyethylene terephthalate) film or PP (polypropylene) film. The upper bonding layerand the lower bonding layerare adhesives, such as hot-melt adhesive or thermosetting adhesive. The adhesive in the present example is hot-melt adhesive. The upper additional layerand the lower additional layerform the upper reinforcement layer and the lower reinforcement layer, respectively, enhancing the mechanical performance of the mica layer. The upper bonding layerand the lower bonding layerdo not serve as reinforcement layers.

101 122 123 122 123 101 102 122 103 123 122 123 In the production process, specifically, hot-melt adhesive is first applied to the upper surface and the lower surface of the mica layerthrough processes such as roll coating, blade coating, or spray coating to obtain the upper bonding layerand the lower bonding layer, respectively; next, a plastic film is applied to each of the upper bonding layerand the lower bonding layer; and finally, the plastic films are attached to the upper surface and the lower surface of the mica layer, respectively through the lamination process, forming the upper additional layerand the upper bonding layer, as well as the lower additional layerand the lower bonding layer. In some examples, the coating thickness of the upper bonding layerand lower bonding layeris 0.01-0.05 mm.

102 103 Those skilled in the art would understand that the materials for the upper additional layerand lower additional layerare not limited to the aforementioned examples.

The various examples of the high-temperature-resistant insulating film in the present application possess excellent high-temperature resistance, with the ability to withstand temperatures of 600-700° C. or higher. Furthermore, the high-temperature-resistant insulating film exhibits exceptional high-temperature-resistant insulation properties, maintaining its insulation even at temperatures of 600-700° C. The high-temperature-resistant insulating film also possesses superior mechanical performance, with a tensile strength of over 100 MPa. Compared to conventional plastic-based insulating films, the high-temperature-resistant insulating film described in the present application not only offers superior heat resistance at elevated temperatures but is also cost-effective.

The applicant has observed that commercially available mica sheets or boards, due to the need for adhesive bonding and pressing during their production process, are prone to fragmentation and detachment during transportation or assembly with other components. In the application environment of certain electronic products, the fragments that fall off may adversely affect the performance stability of the electronic products and are detrimental to the environment.

In contrast, the surface of the high-temperature-resistant insulating film in the present application is no longer the mica layer but the outer surface of each additional layer, which effectively prevents the mica layer from generating fragments, and even if fragments generated, they are unlikely to fall off, thereby averting adverse impact on the performance stability of electronic products.

Furthermore, the applicant has also found that although the thickness of the upper additional layer and the lower additional layer is relatively thin compared to the mica layer, they are capable of significantly improving the mechanical performance of the mica layer. For example, the high-temperature-resistant insulating film of the present application, compared to existing mica sheets or boards, has better flexural resistance and fracture resistance. Even when the high-temperature-resistant insulating film is subjected to bending stress, it is less prone to fracturing. As a specific example, existing mica boards, after bending twice at a 60° angle, fracture and generate fragments that fall off. In contrast, the high-temperature-resistant insulating film described in the present application is capable of being repeatedly bent 7-9 times without fracturing or generating fragments that fall off.

100 130 100 130 101 122 123 130 2 2 FIGS.A toD 2 FIG.A 2 FIG.B 2 FIG.C 2 FIG.D A specific description of the production method for the high-temperature-resistant insulating filmsandis provided below in conjunction with.illustrates the process of the production method for the high-temperature-resistant insulating film.illustrates the process of the production method for the high-temperature-resistant insulating film.is a schematic view of the spray coating equipment for applying the uncured material to the upper surface and the lower surface of the mica layer.is a schematic diagram view of the laminating equipment for pressing the plastic film onto the bonding layersandof the high-temperature-resistant insulating film.

2 2 FIGS.A andC 231 101 207 101 101 207 102 103 101 232 232 102 103 100 As shown in, in step, the uncured material is applied to the upper surface and the lower surface of the mica layerthrough a spray coating process. Specifically, during the production process, a pair of nozzlesof the spray coating equipment are fixed above and below the mica layer, respectively. The mica layeris conveyed from left to right between the pair of nozzles, to apply the uncured upper additional layerand lower additional layeron the upper surface and the lower surface of the mica layer, respectively. After the spraying is completed, stepis initiated. In step, the uncured upper additional layerand lower additional layerare cured through methods such as radiation, heating, or drying, to obtain the high-temperature-resistant insulating film.

2 2 FIGS.B andD 234 101 101 122 123 235 122 123 101 122 123 206 206 122 123 206 101 206 101 206 101 122 123 206 101 101 206 As shown in, in step, hot-melt adhesive is applied on the upper surface and the lower surface of the mica layer, to obtain the mica layercoated with the upper bonding layerand the lower bonding layer. Then, in step, a plastic film is attached to each of the upper bonding layerand the lower bonding layerthrough a lamination process. Specifically, during the production process, the mica layercoated with the upper bonding layerand the lower bonding layeris conveyed from left to right between a pair of rollers; simultaneously, the plastic films are also conveyed through the pair of rollers, applying the plastic films from above the upper bonding layerand below the lower bonding layer, respectively. The speed of application of the plastic film is 2-20 m/min. The pair of rollersrotates in opposite directions, and by heating and pressing, the plastic films are connected to the corresponding bonding layers, thereby attaching the plastic films to the upper and lower surfaces of the mica layer, respectively. In the present example, the rollerabove the mica layerrotates counterclockwise, and the rollerbelow the mica layerrotates clockwise to press the plastic films onto the upper bonding layerand lower bonding layer, respectively. The pressure applied by the two rollerson the mica layerand plastic films passing between them is 3-25 MPa, and the temperature (i.e., laminating temperature) at which the mica layerand plastic films pass between the two rollersis controlled in the range of 95-125° C.

The high-temperature-resistant insulating film described in the present application may be utilized in various electronic products or equipment to aid in heat dissipation. Such electronic products or equipment may include electrical equipment such as battery modules, heating coils, or electric motors.

3 3 FIGS.A andB 3 FIG.A 3 FIG.B 3 3 FIGS.A andB 100 310 310 310 312 311 311 315 313 315 308 313 315 308 312 308 315 312 305 305 312 311 are schematic diagrams illustrating the structure of an example of a battery module comprising the high-temperature-resistant insulating filmof the present application, whereinillustrates the overall structure of the battery module, whileillustrates the disassembled structure of the battery module. As shown in, battery modulecomprises several battery unitsand a housing. The housingcomprises a substantially square box-like bodyand an upper lid, wherein the boxhas an accommodating cavity, and the upper lidis disposed on top of the box-like bodyto enclose the accommodating cavity. A plurality of battery unitsare housed within the accommodating cavityof the box-like body. Each battery unithas its own connecting terminal. After the respective connecting terminalsof these battery unitsare electrically connected according to a predetermined circuit, power and/or charging is provided externally through the main connecting terminal (not shown in the figure) disposed on the housing.

100 312 312 105 100 312 312 105 100 312 312 105 312 100 312 310 The high-temperature-resistant insulating filmis positioned between adjacent battery units, and is also positioned between each battery unitand the box-like body. In some examples, the high-temperature-resistant insulating filmis secured between adjacent battery unitsor between each battery unitand the box-like bodyusing fasteners such as bolts. In some examples, the high-temperature-resistant insulating filmis bonded between adjacent battery unitsor between each battery unitand the box-like bodyusing adhesive. In addition to insulating between adjacent battery units, the high-temperature-resistant insulating filmalso prevents some battery unitsfrom generating excessive heat and reaching high temperatures, which could lead to damage to the battery moduleas a whole.

310 100 312 Furthermore, during the transportation of the battery module, the high-temperature-resistant insulating filmalso provides a certain degree of support, preventing deformation due to mutual compression between the battery units.

312 312 312 315 310 If a high-temperature-resistant plastic film were used between the battery units, it would not only incur higher costs but also provide limited support. Moreover, even high-temperature-resistant plastic films have limited heat resistance. If the temperature of the battery unitbecomes too high, the plastic film may still melt or become damaged. Meanwhile, if conventional mica sheets available in the market are used between the battery units, although the heat resistance is improved, fragments of mica sheets are likely to fall off during transportation and installation. These fragments may fall into the box-like body, potentially affecting the performance of the battery module.

In contrast, the high-temperature-resistant insulating film described in the present application uses mica sheet as an intermediate layer, with additional layers disposed above and below the mica layer. This enhances the mechanical performance of the mica layer while retaining its high-temperature resistance. It also prevents fragments of the mica layer from falling off, making transportation and installation of the high-temperature-resistant insulating film more convenient. Moreover, this design is particularly suitable for heat dissipation and support within battery units.

1. excellent high-temperature resistance, with the ability to withstand temperatures of 600-700° C. or higher, meeting the heat resistance requirements of electronic products and equipment. 2. superior mechanical performance with a tensile strength of over 100 MPa, and the ability to be bent repeatedly without damage, ensuring durability during transportation, packaging, and processing by manufacturers of electronic products and equipment. 3. exceptional insulation performance, especially at high temperatures, meeting the insulation requirements of electronic products and equipment. 4. simple production process. 5. convenient to use and cost-effective, with significantly lower costs compared to typical plastic films. Finally, the high-temperature-resistant insulating film described in the present application has numerous beneficial technical effects. Below are at least some of the technical effects of the high-temperature-resistant insulating film disclosed in the present application:

Although the present disclosure has been described in connection with the exemplary examples outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or foreseeable now or in the near future, may be apparent to those having at least ordinary skill in the art. Therefore, the exemplary examples of the present disclosure set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents. The technical effects and technical problems in this specification are exemplary and not limiting. It should be noted that the examples described in this specification may have other technical effects and may solve other technical problems.